I didn't went to the movie with my sister...

Why did you feel so uncool? Did you think someone would mistake you both for a romantic couple? I don't get it, guess I'm to old.

I don't know how you feel about your sister are close or not but it sure looks like you are feeling ashamed to be seen with... its your sister, she needs to know your there for her even if it means going to the movies with her.

Looking at the relationship that a lot of my friends have with their siblings, I can understand why it might be weird. But my brother and I do things like that all the time, and it feels really normal. On the other hand, we've always been friends, in addition to siblings. Even in high school, when most siblings hated each other, we always hung out in the same circles and had a lot of the same friends and it was not uncommon to find us hanging out together. Now he lives half an hour away from me, but he spends the night here at least once a week, if not more, and we do everything together. He's probably my best friend, after my fiance. Maybe you should try hanging out with your sister more. Who knows? Maybe you can become friends.